Counter-actuating mechanism



Nov. 8, 1949 M. L. NELSON 2,487,469

COUNTER-ACTUATING MECHANI SM Filed Feb. 23, 1943' INVENTOR. ffizrzz'rzL'. velson/ Patented Nov. 8, 1949 COUNTER-ACTUATING MECHANISM Martin L.Nelson, Park Ridge, 111., assignor to Production Instrument Company,Chicago, 111., a corporation of Illinois Application February 23, 1943,Serial No. 476,841

11 Claims.

The present invention relates in general to mechanical counters, and theobject of the invention is to produce an improved device of thischaracter.

A special object of the invention is the production of a more simple andefiicient electromagnetic actuating mechanism for a mechanical counterthan has been known heretofore.

Another object is the production of a new and improved arrangement forrestoring the number wheels of the counter to normal or zero position.

The foregoing and other features of improvement will be described fullyhereinafter, reference being had to the accompanying drawing, in which-Fig. l is a front or plan view of the complete counter, except for thecover;

Fig. 2 is an end view, partly in section, on the line 2-2, Fig. 1;

Fig. 3 is a section, on an enlarged scale, taken on the line 3-3, Fig.1;

Fig. 4 is a section on the line 2-2, Fig. 1, similar to Fig. 2, exceptthat the electromagnet is omitted and the parts are shown on an enlargedscale;

Fig. 5 is a section on the line 5-5, Fig. 1;

Fig. 6 is an end view of the tens number wheel showing the restoringpawl; and

Fig. 7 is a view of the same number wheel from the other end and showingthe ratchet drive mechanism.

Referring to the drawing, the various parts of the counter are supportedon a base In, which may be of molded Bakelite or other suitablematerial, and of rectangular shape, as is apparent from Figs. 1 and 2.

The laminated core of the electromagnet is U-shaped, as seen in Fig. 2,and comprises the two vertical legs H and I2 and the integrally formedyoke l3, the latter being received in a recess in the base Ill near oneend thereof. The magnet core is secured in the recess :by a clampingmember M which is held by the machine screws l5 and [6. This clampingmember I4 rests on top of the yoke I3 and when the screws l5 and [6 aretightened up it holds the magnet core firmly in place. The windings ofthe electromagnet are indicated at I! and [8.

At the opposite end of the base is disposed an L-shaped supportingbracket l 9 which is secured to the base ID by screws as indicated inFig. 1.

The main shaft 20 is rotatably supported on the bracket I9 at one endand by means of a plate 2| at the other end. The plate 2| is secured tothe legs I I and l 2 of the magnet core by means of bolts 22, 23 and 24,and is made of brass or other non-magnetic material. The shaft 20 may berotated in its bearings by means of a knob 25. This knob is preventedfrom turning on the shaft by a cross pin '26, the ends of which arereceived in a slot in the base of the knob; and is held on the shaft bya screw 21' which is threaded into the end thereof.

Mounted on the shaft 28 in the usual manner are a plurality of numberwheels corresponding to the different orders of digits in the decimalsystem. The units number wheel is indicated at 30 and the tens numberwheel at 33. Other number wheels corresponding to successively higherorders of digits are mounted to the left of the tens number wheel 33,but are not shown in detail.

The tens number wheel and those corresponding to the higher orders ofdigits are all alike. Fig. 6 shows the tens number wheel 33 as seen fromthe left hand end. There is an annular recess 35 in the end of thewheel, which afiords space for mounting the pivoted pawl 36, which isspring-pressed against the shaft 20. The shaft is provided with alongitudinally extending ratchet tooth for coaction with the pawls suchas 36. As will be readily understood from Fig. 6, the number wheel shownis rotatable in a counterclockwise direction on the shaft. It will alsobe appreciated that the shaft is rotatable in a clockwise directionwithout disturbing the number wheel; but if the shaft is rotated in acounterclockwise direction, .the ratchet tooth on the shaft will engagethe pawl and. thereby rotate the number wheel. This arrangement isprovided for restoring the number wheels to zero position, as will bedescribed more fully later on.

The units number wheel 30 is also provided with a restoring pawl asshown in Fig. 6. At the right hand end the units number wheel isprovided with a star wheel 3! and a ratchet wheel 32. These parts areformed integrally with the number wheel. It ma be mentioned here thatthe number wheels are preferably of molded Bakelite or other suitableplastic.

A transfer mechanism is provided through the medium of which each numberwheel except the last controls the number wheel of the next higherorder. This mechanism includes the transfer pinions such as 40 and 4|,which are rotatably mounted on the shaft 42, Fig. 1. This shaft issupported at one end on the bracket I 9 and at the other end on theplate 2 l.

Each time the units number wheel, for example, advances to display thedigit 0, it rotates the pinion 4| according to the principle of theGeneva movement. The pinion 4| is in mesh with and rotates the gear 34,which is mounted adjacent the tens number wheel on a hub 3'! with whichthe latter is provided. The gear wheel 33 rotates the tens number wheelby means of a ratchet and pawl mechanism.

Fig. 7 shows the arrangement clearly. The gear is supported on the hub31 and is provided with the two pawls 38 and 39, which arespring-pressed outwardly so as to cooperate with the internal ratchetteeth on the number wheel There are ten peripherally disposed ratchetteeth, corresponding to the ten digits.

The armature of the electromagnet is laminated and is indicated at 43.The armature is rotatably mounted on the shaft by means of the bearingsleeve or bushing M. The laminations of the armature may be heldtogether by rivets, as indicated in Fig. 2.

The armature is somewhat thicker than the pole pieces, as shown in Fig.1, and the left hand lamination is longer than the others, forming anarm it which overlaps the left hand pole of the electromagnet, as seenin Fig. 2. At the end of arm 3% there is a stud M, which is riveted tothe arm, and on the stud is mounted a pawl 49 which cooperates with theratchet wheel 32. The pawl is held against the ratchet wheel by a spring59, the coils of which surround a part of stud i! and which is tensionedbetween the rear end of the pawl 9 and a pin 5! on arm 16. This Thearmature 33 is biased to its normal posi- :5

tion, that is, the position in which it appears in Figs. 1 and 2, bymeans of a coil spring 52 one end of which is fastened to the base I0and the other end of which is hooked around the stud ll near the endthereof. The stud may be grooved as shown in Fig. 1 to prevent thespring 52 from slipping ofi. A bumper spring is secured to the plate 2!by bolt 23 and extends tothe left and forward over one end of armatureit. The end of this spring is engaged by armature 33 just before itreaches normal position.

The reference numeral 38 indicates the stop pawl, which is pivotallysupported on shaft 42,

the same shaft that carries the transfer pinions such as ii. The stoppawl includes two parts, a curved arm which is engaged by the stud 4!when the armature i3 is in actuated position, and a dog 54 which has acurved cam surface cooperating with the star wheel 3!. these parts thereis a space in which the stud fill oscillates during operation of thearmature, said space ending at the bottom in a rounded Between notch 56in which the stud ll rests when the armature 43 is in normal position.

The stop pawl 48 is biased toward the star wheel all by means of a coilspring 53. One end of this spring is attached to base [0 and the otherend is hooked over a pin which projects from the stop pawl, as shown inFig. 4.

At the left hand end of shaft 20 and between the last number wheel andthe bracket I9 there are two arms Eli and (ii. Arm fill is rotatable onshaft 2%, while arm 6| is fixed thereto by a set screw or in anysuitable manner. There are also two pins 52 and which are fixed to thebracket it. These parts are included in the number wheel restoringmechanism, as will be explained presently.

The construction of the improved counter having been described, itsoperation will now be explained briefly. For this purpose it will beassumed that the windings l! and I8 of the electromagnet are connect-edin a suitable electrical circuit over which impulses of current may bedelivered to the counter. The impulses may be produced as the result ofsuccessive operations of some machine, for example, and the counter maybe employed to count the impulses and register the total number thereof.

As previously mentioned, the armature 43 is biased to the position inwhich it appears in Figs. 1 and 2 by the coil spring 52. In thisposition the operative end of pawl 49 is resting in one of the notchesin the ratchet Wheel 32, as shown in Fig. 3, for example. Also the stud41 is resting in the bottom of the notch 56 in the stop pawl 68. Thisholds the curved dog 54 against the star wheel 3! and prevents anyaccidental rotation of the units wheel in a forward direction. The unitswheel is not positively locked against forward rotation, and can beadvanced by rotating the shaft 20, which causes the teeth of the starwheel to oscillate the stop pawl 28 and armature 43 slightly, but thetension in springs 52 and 53 is sufiicient to bias the dog 54 quitefirmly in the direction of the star wheel to prevent any inadvertentrotation of the units wheel such as might otherwise be caused by a shockor jar.

When the electromagnet is energized by an impulse of current, thearmature 43 is attracted and is rotated on shaft 20 in a clockwisedirection to the position in which it is shown in Fig. 4, therebyadvancing the units number wheel 30 by means of pawl 49 and ratchetwheel 32. The units number wheel is advanced an angular distance equalto the spacing between digits and is thus caused to display the digit 1,assuming that the initial setting was zero.

At the beginning of the movement of the armature, the stud t? leaves thenotch 56 in the stop pawl and thus leaves the pawl free to move awayfrom the star wheel 3! as a tooth of the wheel rides past the dog 53.That is, the stop pawl is free to move except for spring 53, whichyields to permit the described action of the stop pawl responsive to thepositive drive of the ratchet and star wheels by the pawl l9.

At the end of the movement of the armature the stud ll engages thecurved arm 55 of the stop pawl, as shown in Fig. 4. There is a magneticcushioning effect as the armature becomes aligned between the poles ofthe electromagnet, which substantially eliminates the shock as the studengages the arm 55. In this position of the armature t3 and stud ii thestop pawl 48 is positively locked against movement away from the starwheel 3!, and hence the latter is locked by the dog 5i, which is nowresting in the next adjacent notch of the star wheel. The describedlocking of the stop pawl prevents overrun by the units number wheel andinsures that it will be rotated only one notch of the ratchet wheel.

Upon cessation of the current impulse the electromagnet becomesdeenergized and the armature is rotated back to normal position by thespring 52. During the return movement the stop pawl 68 is free ofrestrain by the stud ii; but the dog 56 is held against the star wheel3! by the spring 53 with ample force to prevent retrograde movement ofthe units number wheel due to the slight friction between pawl t9 andthe ratchet wheel as the pawl slides over the wheel preparatory todropping into the notch behind the next tooth. In the fully restoredposition of the armature the stud 4'! rests in the notch 56 of the stoppawl, as previously described. Just prior to reaching this position thearmature 43 engages the buffer spring 45 which substantially eliminatesthe shock which would otherwise occur when the stud 47 reaches the notch56.

The foregoing explanation covers the operation of the counter inresponse to one impulse. Subsequent impulses operate the countersimilarly, with the result that the units number wheel is rotated stepby step to increase its reading by one (1) each time an impulse isreceived. After nine impulses have been counted, the next impulse stepsthe units number wheel tozero; but at the same time the transferarrangement between the units number wheel and the tens number wheeladvances the latter wheel one step and causes it to display the digit 1.The number displayed is therefore the number ten which is equal to thenumber of impulses received.

It will be understood that any number of impulses may be counted up tothe capacity of the counter. If six number wheels are provided, thecapacity is 999,999. The impulses to be counted may be received atirregular intervals or they may be rapidly recurring impulses of aseries. Due to the improved armature and pawl construction, togetherwith the stop pawl arrangement, the drive is exceedingly fast andaccurate and the counter will respond properly to ii-- pulses receivedat a rate in excess of impulses per second.

In order to set the counter to zero, the knob is rotated by hand in acounterclockwise direction (as seen from the right in Fig. 1) as far asit can be turned. The knob 2-5 rotates shaft 29 in a clockwise directionas seen in Fig. 5, thereby also rotating the arm 5i, which eventuallyengages the arm and rotates it also. The rotation is stopped when thearm til engages the pin 62. The parts are shown in this position in Fig.5.

The knob 25 is now rotated in the opposite direction, thereby rotatingthe shaft 2!} in a counterclockwise direction, as seen in Fig. 5. Arm 6|rotates with shaft 25} and disengages itself from arm 60. Fig. 6 showsthe shaft 20 in the same position as in Fig. 5, while the number Wheelis in the proper position to display the digit 1. From theseconsiderations it will be appreciated that as shaft 20"is rotated thetooth on the shaft will eventually reach the pawl 36, whereupon furtherrotation of shaft 20 will carry the number wheel along and cause it tosuccessively display the digits 8, 9 and then zero (0). The other numberwheels are similarly picked up by the shaft 28, either sooner or laterdepending on the position in which they happen to be standing, and allthe wheels are thus simultaneously reset to zero. It should be pointedout in this connection that the shaft is rotated somewhat more than 360degrees so that a number wheel already in zero position is neverthelesspicked up at the start of the return rotation of shaft 20 and is rotatedthrough 360 degrees, or from zero to zero.

During the return rotation of shaft 20 the arm 6| eventually engages thearm Ell and moves it around until it engages the pin 63. This positivelystops the rotation of shaft 20. The arrangement is such that therotation of the shaft is stopped just as the number wheels reach zeroposition, which avoids the possibility that the operator mightinadvertently rotate the number wheels too far. As a matter of fact thenumber wheels can be rotated slightly beyond the zero position, but thewheels are self-aligning within certain limits, and they automaticallyreturn exactly to zero position as soon as the shaft 20 is released.

In further explanation of the automatic aligning feature, it will beunderstood by reference to Fig. 7 that as, the number wheel 33, forexample, is advanced to zero position the pawl 38 (also 39) will dropinto the notches of the internal ratchet on the number wheel one afterthe other. These notches serve to align the corresponding digits withrespect to the sight opening of the counter,

as will be understood from the previous explanation of the transfermechanism. Now when the number wheel displays the digit zero, the pawlsdrop into the corresponding notches, and if the number wheel is advancedsomewhat beyond this point the pawls start to lift out of the notches,with the result that when the shaft 28 is released the number wheel isrestored exactly to zero by the camming action of the pawls.

From the foregoing it will be seen that the invention provides a highlydesirable mechanical counter, which is compact in design, economical tomanufacture, and very efficient and accurate in operation.

While the drawing shows an excellent construction and design of theparts, which has been tested and found to give excellent results, it isrecognized that modifications may be made without departing from theprinciples of the invention. I do not therefore wish to be limited tothe ,exact form of the invention as illustrated and described, butdesire to include and have protected by letters patent all forms andmodifications which come within the scope of the appended claims.

I claim:

1. In a mechanical counter having a shaft and counting means rotatablymounted thereon and including a units number wheel carrying ratchetteeth, a device for angularly advancing said number wheel step by step,said device comprising an electromagnet having pole pieces disposed onopposite sides of said shaft, said pole pieces having arcuate pole facesdefining a circle not greater in diameter than said number Wheel, a

.bi-polar armature rotatable on said shaft between said pole faces, apawl carried by said armature for advancing the ratchet to advance saidnumber wheel responsive to angular displacement of said armature whenthe electromagnet is energized, a pivotally mounted member forming stopsfor positively limiting the angular displacement of said armature ineither direction of operation thereof, and resilient buffer means forengagement with one pole of said armature to cushion the angulardisplacement thereof in one direction of operation.

2. In a mechanical counter having a shaft and a units number wheelrotatably mounted .thereon and carrying a star wheel and a ratchet wheelassociated therewith and rotatable therewith as a unit, a device forrotating said ratchet step by step to rotate the associated star wheeland number Wheel accordingly, said device comprising an electromagnet,an armature for said electromagnet rotatably mounted on said shaft, apawl supported on said armature and adapted to advance said ratchetwheel when the armature is rotated responsive to energization of saidelectromagnet, a pivoted dog cooperating with said star wheel, and meanswhereby said armature controls said dog to lock the star wheel andratchet wheel in advanced position.

3. A counter as claimed in claim 2, together with means for controllingsaid dog by. the armature in its normal position to prevent accidentalrotation of the number Wheel, star wheel, and ratchet wheel associatedtherewith.

4. In a mechanical counter having a units number wheel, a star wheel anda ratchet wheel disposed side by side on a shaft and rotatable thereonas a unit, a device for angularly advancing said ratchet wheel step bystep to advance said star wheel and associated number wheel accordingly,said device comprising an armature rotatably mounted on said shaftaxially adjacent said ratchet wheel, an electromagnet for rotating saidarmature from a normal position and a spring for restoring the same tonormal, a stud supported on said armature, a pawl pivoted on said studfor rotating said ratchet wheel responsive to rotation of said armature,and a pivoted member controlled by said stud and adapted to cooperatewith said star wheel to prevent overrun of the ratchet wheel andassociated parts when the armature is rotated by energization of saidmagnet.

5. In a mechanical counter having a shaft carrying a units number wheel,a star wheel and a ratchet wheel associated therewith and rotatablymounted on said shaft as a unit, a device for angularly advancing saidratchet wheel step by step to advance the associated star wheel andnumber wheel accordingly, said device comprising an armature rotatablymounted on said shaft, an electromagnet for rotating said armature uponenergization of the magnet, a pawl operated by the armature to rotatesaid ratchet and therewith the star wheel and associated number wheel, asingle spring for restoring said armature and said pawl, a pivoted dogfor cooperation with said star Wheel, means whereby said armature holdssaid dog against the star wheel in two positions of the armaturecorresponding to the energized and deenergized conditions of saidelectromagnet, and a spring for holding said dog against said star wheelwhen the armature is moving between said positions.

6. A device of the class described comprising a shaft, an elementrotatably mounted on said shaft and forming an operating member and anexteriorly peripherally toothed ratchet which is rotatable therewith asa unit, an armature rotatably mounted on said shaft adjacent thereto butaxially spaced therefrom, electromagnetically actuated means forangularly displacing said armature, a pawl actuated by said armatureresponsive to angular displacement thereof by said electromagneticallyactuated means for rotating said ratchet to rotate said operatingmemher, and a single spring means for maintaining said armature innormal position relative to said electromagnetically actuated means andfor also maintaining said pawl in normal position relative to saidratchet.

7. The structure defined in claim 6, together with a pivotally mountedmember forming stops for limiting the angular displacement of saidarmature in either direction of operation thereof.

3. The structure defined in claim 6, together with a star-wheel disposedbetween said operating member and said ratchet and rotatable therewith,and a pivotally mounted member forming stops for limiting the angulardisplacement of said armature in either direction of operation thereofand also forming a detent for engagement with said star wheel to controlthe rotation thereof and therewith the rotation of the associatedoperating member responsive to rotation of said ratchet.

9. The structure defined in claim 6, together with a device forcontrolling the operation of said armature and of said ratchet, saiddevice comprising a star-wheel coupled with said ratchet and with saidoperating member and rotatable therewith, a pivotally mounted memberhaving an arm for engagement with said starwheel, and an extension onsaid member for coaction with the armature in the extreme operativelyactuated positions thereof.

19. The structure defined in claim 6, together with a device forcontrolling the operation of said armature and of said ratchet toprevent overtravel thereof, said device comprising a starwheel coupledwith said ratchet and with said operating member and rotatabletherewith, a pivotally mounted control member, an arm on said controlmember for detent engagement with said star-Wheel, means on said controlmember forming a groove for coaction with said armature in normalposition thereof, and an extension on said control member for coactionwith said armature in the extreme operatively actuated position thereof.

11.. A device of the class described comprising a shaft, an elementrotatably mounted on said shaft and forming thereon an operating memberfrom which extends in axial direction an exteriorly peripherally toothedstar wheel and axially adjacent thereto an exteriorly peripherallytoothed ratchet, an armature mounted for angular oscillation on saidshaft axially adjacent said ratchet, electromagnetically actuatedimpulse-responsive means for angularly displacing said armature from anormal to an operated position, a pivotally mounted pawl actuated bysaid armature responsive to angular displacement thereof by saidelectromagnetically actuated means, said pawl being in coactingengagement with said ratchet for angularly advancing such ratchet torotate said star wheel and associated operating member, and a pivotallymounted member forming stops for limiting the angular displacement ofsaid armature in either direction of oscillation thereof and alsoforming an extension for coacting detent engagement with said star wheelto control the rotation thereof thereby controlling the rotation of itsassociated operating member responsive to angular advance of saidratchet.

MARTIN L. NELSON.

CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 961,358 Kinney June 14, 19101,370,540 Hussey Mar. 8, 1921 1,459,730 Harris June 26, 1923 2,925,978Getty ec. 31, 1935 2,089,936 Ahlburg Aug 1'7, 193'? 2,165,733 SpaunburgJuly 11, 1939 2,239,310 Allen Apr. 22, 1941 FOREIGN PATENTS NumberCountry Date 325,296 Great Britain Nov. 20, 1928

